The present invention relates generally to the field of orthodontics, and more particularly to an apparatus for bonding an orthodontic bracket to a tooth and a method for making the same.
The fundamental objectives in orthodontics are to move a patient's teeth to a position where the mechanical function of the dentition is optimized and to improve the aesthetic appearance of the patient's teeth. The traditional method that orthodontists use is to attach brackets and wires onto the patient's dentition. Once mounted on the teeth, the wires exert continual light forces through the brackets on the teeth. These forces initiate the body's biological bone remodeling response and the teeth gradually progress toward their desired final positions. During the treatment period, the treatment professional reactively adjusts the wires and bands to provide a new force and move the teeth generally toward their desired or final destination.
Orthodontic brackets are often bonded directly to the patient's teeth. Typically, a small quantity of adhesive is placed on the base of each bracket and the bracket is then placed on a selected tooth while the patient is in the dental chair. Before the adhesive is set, the bracket is maneuvered to a general location on the tooth. Once the adhesive has hardened or cured, the bracket is bonded to the tooth with sufficient strength to withstand subsequent orthodontic forces as treatment progresses. Bonding templates can be used by an orthodontist for positioning the bracket at the desired location on the tooth. However, one shortcoming with this technique is the difficulty in cleaning adhesive “flash” that typically forms on the teeth around the edges of the brackets under the template. The adhesive flash under the template is not easily accessible while the template is on the teeth prior to curing of the adhesive. As cleaning of adhesive flash after it has hardened or cured is difficult, the amount of time needed to carry out the direct bonding procedure is thus increased.
One way to overcome some of the limitations of direct bracket placement is with indirect bonding. Typically, a routine impression of each of the patient's upper and lower dental arches is taken and either sent to a lab or used in the office to create a replica plaster model of each impression after the patient has left the office. Brackets are bonded to the sealed plaster models using a temporary adhesive. A transfer tray is then made by placing matrix material over both the model and brackets. The matrix material then assumes a configuration that matches the shape of the replica teeth of the plaster model with the brackets in the desired position. The matrix material then polymerizes and hardens to form a tray. The temporary adhesive is removed, and permanent adhesive is placed on the base of each bracket in the tray, which is then placed over matching portions of the patient's dental arches. Since the configuration of the interior surface of the tray closely matches the respective portions of the patient's dental arches, each bracket location is transferred onto the patient's teeth at precisely the same location that corresponds to the previous location of the same bracket on the plaster model. The adhesive is hardened or cured and the matrix removed, leaving the brackets in the desired positions on the teeth. The tray may be provided with bracket placement “fingers,” which allow access to tooth surfaces around the brackets, facilitating cleanup of any adhesive flash that may form on the teeth. The indirect bonding method, however, is labor intensive and the brackets may become dislodged during the removal of the matrix from the dental arches. Thus, a direct bonding template that would allow cleanup of adhesive flash prior to curing would be desirable.